title: A DNA-topoisomerase-II-binding protein with eight repeating regions similar to DNA-repair enzymes and to a cell-cycle regulator.
abstract: A two-hybrid system was used to isolate factors that interact with the C-terminal region of DNA topoisomerase IIbeta. A positive clone isolated from a HeLa cDNA library encoded 1522 amino acid residues (molecular mass 170670). The protein, designated topoisomerase-IIbeta-binding protein 1 (TopBP1), interacted with the C-terminal region of topoisomerase IIbeta synthesized in vitro. A database search indicated that TopBP1 possessed eight regions similar to regions of Rad4, Cut5, Ect2, Rev1 and X-ray repair cross-complementing 1 (XRCC1) proteins and a region similar to auto-modification sites of poly(ADP-ribose) polymerase, suggesting that TopBP1 supported catalytic reactions of topoisomerase II through transient breakages of DNA strands.
authors.affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamane
authors.forename: M
authors.initials: M
authors.lastname: Kawabata
authors.forename: T
authors.initials: T
authors.lastname: Tsuruo
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000737:chemistry*; D003001:Cloning, Molecular; D011088:DNA Ligases / Q000737:chemistry* / Q000378:metabolism; D004250:DNA Topoisomerases, Type II / Q000378:metabolism*; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D011485:Protein Binding; D012333:RNA, Messenger / Q000032:analysis / Q000737:chemistry; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C110513:TOPBP1 protein, human; D004250:DNA Topoisomerases, Type II; D011088:DNA Ligases